Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services exceeded 5 billion and continues to grow quickly. The demand of wireless data traffic is rapidly increasing due to growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, “note pad” computers, net books, and eBook readers. In order to meet the high growth in mobile data traffic, improvements in radio interface efficiency and communication technology is of paramount importance. One such improvement is the growing use of two-dimensional advanced antenna systems in multi-user (MU) multiple-input multiple-output (MIMO) communication systems.